Flushless transactional layer

ABSTRACT

Writing data to storage utilizing a diverged thread for asynchronous write operations is provided. On a first thread, an analysis engine analyzes and identifies changed information to write to storage and an I/O manager copies the writes into buffers and places the buffers into a queue, while on a second thread, a flushless transactional layer (FTL) drive executes the writes to storage. By allowing the analysis to continue and enqueue writes on a first thread while the writes are written to storage on a second thread, the CPU and I/O of the system are utilized in parallel. Accordingly, efficiency of the computing device is improved.

BACKGROUND

Many computing architectures implement cache as a means for addressing amismatch between the performance characteristics of a computing device'sstorage device (e.g., magnetic recording media, solid state storage) andthe performance requirements of the device's central processing unit(CPU) and application processing. For example, when an applicationissues a write command, the system may write the data into the cache,where periodically, the data from the cache is flushed to the storagedevice.

However, flushing a write cache is an expensive operation, which candegrade performance. When flushing data from the cache to the storagedevice, the storage device flushes the entire system. That is, thestorage device writes everything in the cache for all drives to storage,which can cause a computing device to incur a performance penalty,particularly on a low-end device with a limited bandwidth input/output(I/O) subsystem. Additionally, there may be a risk of loss or corruptionof data if power is lost while there is data in the disk's write cachethat has not been written to storage.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription section. This summary is not intended to identify keyfeatures or essential features of the claimed subject matter, nor is itintended as an aid in determining the scope of the claimed subjectmatter.

Aspects are directed to an improved write transaction, includingimproved systems, methods, and computer readable media, for writing datato storage utilizing a diverged thread for asynchronous writeoperations. On a first thread, an analysis engine analyzes andidentifies changed information to write to storage and an I/O managercopies the writes into buffers and places the buffers into a queue,while on a second thread, a flushless transactional layer (FTL) driveexecutes the writes to storage. By allowing the analysis to continue andenqueue writes on a first thread while the data is written to storage ona second thread, the CPU and I/O of the system are utilized in parallel.Accordingly, efficiency of the computing device is improved.

Examples are implemented as a computer process, a computing system, oras an article of manufacture such as a computer program product orcomputer readable media. According to an aspect, the computer programproduct is a computer storage media readable by a computer system andencoding a computer program of instructions for executing a computerprocess.

The details of one or more aspects are set forth in the accompanyingdrawings and description below. Other features and advantages will beapparent from a reading of the following detailed description and areview of the associated drawings. It is to be understood that thefollowing detailed description is explanatory only and is notrestrictive of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this disclosure, illustrate various aspects. In the drawings:

FIG. 1 is a simplified block diagram showing an example operatingenvironment and components of an example flushless transactional system;

FIG. 2 is an illustration of an example write transaction;

FIG. 3 is a flow chart showing general stages involved in an examplemethod for writing data to storage utilizing a diverged thread forasynchronous write operations;

FIG. 4 is a block diagram illustrating example physical components of acomputing device; and

FIGS. 5A and 5B are simplified block diagrams of a mobile computingdevice.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings.Wherever possible, the same reference numbers are used in the drawingsand the following description refers to the same or similar elements.While examples may be described, modifications, adaptations, and otherimplementations are possible. For example, substitutions, additions, ormodifications may be made to the elements illustrated in the drawings,and the methods described herein may be modified by substituting,reordering, or adding stages to the disclosed methods. Accordingly, thefollowing detailed description is not limiting, but instead, the properscope is defined by the appended claims. Examples may take the form of ahardware implementation, or an entirely software implementation, or animplementation combining software and hardware aspects. The followingdetailed description is, therefore, not to be taken in a limiting sense.

Aspects of the present disclosure are directed to a method, system, anddevice for processing a write transaction to storage utilizing adiverged thread for asynchronous write operations. On a first thread, ananalysis engine analyzes and identifies changed information to write tostorage and an I/O manager copies the writes into buffers and places thebuffers into a queue. Concurrently, on a second thread, a flushlesstransactional layer (FTL) drive executes the writes to storage.Accordingly, the CPU and I/O of the system are utilized in parallel.

With reference now to FIG. 1, a simplified block diagram of one exampleof an operating environment 100 for a flushless transactional system isshown. The example system includes a computing device 102 in the form ofa desktop computer, laptop computer, tablet computer, handheld computingdevice, mobile communication device, wearable device, gaming device, andthe like. The computing device 102 includes a non-volatile storagedevice 140 for booting the computing operating system (OS) 132, storingapplications, and storing data. In some examples and as illustrated inFIG. 1, the storage device 140 is a disk drive 116 having a diskassembly 122 that includes a non-volatile memory storage medium such asone or more disks 124, a read/write head 126 for reading and writing tothe disk 124, and a spindle/armature assembly 128 for moving theread/write head 126 to locations on the disk 124. A controller 120commands the disk assembly 122 to read data from the disk 124 or writedata to the disk 124. Although illustrated as a disk drive 116, in someexamples, the storage device 140 is a solid state device, where data iselectronically stored on interconnected flash memory chips.

The OS 132 is illustrative of a hardware device, firmware system, orsoftware system operative to manage the computing device's 102 resources(e.g., central processing unit (CPU), memory, disk drives, I/O devices,etc., establish a user interface, and execute and provide services forapplications 104.

The flushless transactional system includes at least one application 104executing on the computing device 102. For example, the application 104is operable to access, modify, or generate data. The application 104 maybe one of various types of applications or a suite of applications, suchas, but not limited to, an electronic mail and contacts application, aword processing application, a spreadsheet application, a databaseapplication, a slide presentation application, a drawing orcomputer-aided drafting application program, a personal informationmanagement application, an Internet browser application, etc.

The application 104 is operable to issue an I/O command, such as anapplication programming interface (API) call to write data to storage.According to an example, the application 104 issues the write request toan I/O manager 108. For example, in response to a user-initiated savefunction, automated save function, open function of a file, etc., theapplication 104 generates a persisted model of the data file includingdata content and metadata (e.g., formatting, style), which is sent in adata packet with the write request.

The computing device 102 is comprised of various devices that provideI/O to and from the outside world (e.g., keyboards, mice, audiocontrollers, video controllers, disk drives 116, networking ports).Device drivers, such as storage device driver 134, provide the softwareconnection between the various devices and the OS 132. The I/O manager108 is illustrative of a hardware device, firmware system, or softwaresystem operative to manage the communication between applications (e.g.,application 104) and interfaces provided by device drivers. For example,the I/O manager 108 is operative to manage communication between theapplication 104 and the storage device driver 134, such as a writerequest issued by the application 104.

The storage device driver 134 is illustrative of a hardware device,firmware system, or software system that operates or controls thestorage device 140 (e.g., disk drive 116 or SSD). The storage devicedriver 134 may serve as a software or hardware interface to the storagedevice 140 (e.g., disk drive 116) for enabling the OS 132 or otherapplications (e.g., application 104) to access functions of the datastorage device 140 without needing to know operating details of the datastorage device 140. That is, the storage device driver 134 acts as atranslator between the OS 132 and the data storage device 140.

When the I/O manager 108 receives a write request, the I/O manager 108is operative to call an analysis engine 106 to determine the data towrite to storage. For example, the analysis engine 106 determinesdifferences between the generated persisted model of the data filegenerated by the application 104 and sent with the write request and alast-saved version of the data file. The analysis engine 106 isillustrative of a hardware device, firmware system, or software systemoperative to perform a read of the data file, perform a read of thelatest version of the data file last written to storage, and analyze thedata files for identifying changed information made since the last save.

According to an example, the last-saved version of the data file is readinto a cache 118 managed by a cache manager 136. The cache manager 136is illustrative of a hardware device, firmware system, or softwaresystem that is operative to read data from the storage device 140, andtemporarily store data files for fulfillment of future requests for thedata. For example, when the last-saved version of the data file isstored in the cache 118, the cache manager 136 fulfills a request by theanalysis engine 106 to read the last-saved version of the data file fromthe cache 118 for its analysis.

According to an aspect, for each cached file in the cache 118, the cache118 stores metadata, such as synchronization information, endpointconnection information, etc. According to an example, a cached file'scontents are broken into pieces or a collection of blobs and stored in acontainer file in the cache 118. The container file includes a headercomprising various pieces of information, such as an identifier for theversion of the container file, location of a transaction log used toproduce the current state of the data, etc.

The flushless transactional system includes an FTL drive 114, which isincluded in or operationally attached to the storage device driver 134.The I/O manager 108 is operative to reroute a write request to the FTLdrive 114. For example, the I/O manager 108 collects the changedinformation writes determined by the analysis engine 106, and copies thewrites into a queue 130 within the FTL drive 114. The FTL drive 114 isillustrative of a device, device firmware, or software application thatcomprises the queue 130 and a buffer pool 110 comprising a plurality ofbuffers 112, and is operative to enqueue the writes in the buffers 112and execute the writes to the storage device 140 (e.g., the disk drive116). According to an aspect, the FTL drive 114 enqueues and issues thewrites to be written directly to the storage device 140 rather than to acache and later flushed to the storage device 140.

According to an example, the system processes a write transaction on twoparallel threads: as the analysis engine 106 analyzes and identifieswrites and the I/O manager 108 copies the writes into buffers 112 andplaces the buffers 112 into the queue 130 on a first thread, the FTLdrive 114 executes the writes on a second thread.

According to an aspect, by allowing the analysis to continue and enqueuewrites on a first thread while the data is written to storage on asecond thread, the CPU and I/O of the system are utilized in parallel.Accordingly, efficiency of the computing device 102 is improved. Forexample, flushing the cache 118 is an expensive process, as everythingin memory is written to disk 124. Automatically writing changes made toa data file to disk instead of writing to cache 118 and performing alarge volume write to disk at the end levels out computational resourceusage. Accordingly, the save process is faster and applications (e.g.,application 104) are not impacted by waiting for a flush to complete.Thus, the user experience is improved, as a user of the application 104does not have to wait for everything in the system cache to write todisk before continuing to use the application 104.

With reference now to FIG. 2, an example write transaction 200 isillustrated. According to the illustrated example, the lower line isillustrative of a first thread in the application code 202. For example,when a write request 204 is issued by the application 104 for a datafile, the application 104 creates a stream of data, which may includethe data file's content and metadata generated or modified by a user ofthe application 104. A first read operation 206 a is performed by theanalysis engine 106, where the data stream generated by the application104 is read and compared against the last saved version of the data filefor identifying changes to the data file since the last save to the diskdrive 116. Additionally, the I/O manager 108 pulls one or more freebuffers 112 from the buffer pool 110, copies the one or more changedinformation writes identified by the analysis engine 106 into the freebuffers 112, and places the buffers 112 into the FTL drive queue 130.The number of write operations 210 a-n (collectively, 210) is dependenton the size of the data to be written.

As illustrated, a single divergence point 208 occurs in the writetransaction 200 at a first write operation 210 a, when, on a separatethread, the FTL drive 114 pulls a filled buffer 112 from the queue, andexecutes the enqueued write to storage (e.g., the disk drive 116), andreturns the now free buffers 112 to the buffer pool 110 for reuse as newwrite calls are made. When the queue 130 is empty, the write to disk iscomplete.

One or more convergence points 212 a,b (collectively, 212) occur in thewrite transaction 200 to ensure that all write operations 210 arefinished before proceeding. For example and as illustrated, aconvergence point 212 a before the second read operation 206 b occurswhen the I/O manager 108 ensures that the write operations 210 arefinished before proceeding. For example, the I/O manager 108 determineswhether the queue 130 is empty or whether there are additional bufferedwrites that have not been written to storage. If the queue 130 is notempty, the I/O manager 108 waits in blocks for the write operations 210to finish. According to an example, the convergence point 212 provides aguarantee that a next read operation 206 b will pick up on the changesmade by the write operations 210. As illustrated, a final convergencepoint 212 b occurs at transaction commit. For example, the finalconvergence point 212 b brings the system to a coherent state at the endof the write transaction 200.

Having described an operating environment, a write transaction 200example, and various aspects with respect to FIGS. 1-2, FIG. 3illustrates a flow chart showing general stages involved in an examplemethod 300 for flushless writing of data to disk. The method 300 beginsat start operation 302, where an application 104 issues a write request204 in response to a user-initiated save function, an automated savefunction, an open function of a file, etc. The method 300 proceeds to adata stream generation operation 304, where the application 104generates a stream of data and metadata to be written to storage (e.g.,to the disk drive 116).

The method 300 proceeds to an analysis operation 306, where the analysisengine 106 performs a read of the data stream and a read of the datafile written to the disk drive 116 for determining changes made to thedata file since the last save to storage (e.g., the disk drive 116).

The method 300 proceeds to an analysis decision operation 307, where adetermination is made as to whether there is change information to writeto storage. When the analysis engine 106 identifies change information,the method 300 proceeds to a buffer write operation 308, where the I/Omanager 108 collects the identified changes to write to storage, copiesthe writes into one or more free buffers 112 stored in the buffer pool110, and places the one or more filled buffers 112 into the queue 130.According to an aspect, the analysis operation 306, the analysisdecision operation 307, and the buffer write operation 308 continue inparallel on a first thread as the method 300 proceeds to operations310-314.

A divergence point 208 occurs in the write transaction 200 as the method300 proceeds to a queue status determination operation 310, where adetermination is made as to whether the queue 130 is empty or whetherthere are filled buffers 112 that are enqueued. If a determination ismade that the queue 130 is not empty, the method 300 proceeds to a writeoperation 312, where the FTL drive 114 pulls a filled buffer 112 fromthe queue 130, and executes the write to storage. For example, the FTLdrive 114 issues a command to the controller 120 via the storage devicedriver 134 to write the data to the storage device 140 (e.g., the harddrive 116 to write to the disk 124).

The method 300 then proceeds to a buffer return operation 314, where theFTL drive 114 returns the now-empty buffer 112 to the buffer pool 110 sothat it can be reused for additional writes. The method 300 then returnsto the queue status determination operation 310.

If a determination is made that the queue 130 is not empty at the queuestatus determination operation 310, the FTL drive 114 continues to issuethe writes to storage, and the I/O manager 108 waits for the writes tocomplete.

If a determination is made that the queue 130 is empty at the queuestatus determination operation 310, a convergence point 212 occurs inthe write transaction 200 as the method 300 proceeds to a cachesynchronization operation 316, where the cache is updatedcorrespondingly with the changes made by the write operations 210. Forexample, a new transaction log record describing the writes is added tothe cache 118, and the system is brought to a coherent state at the endof the write transaction 200. The method 300 ends at operation 398.

While implementations have been described in the general context ofprogram modules that execute in conjunction with an application programthat runs on an operating system on a computer, those skilled in the artwill recognize that aspects may also be implemented in combination withother program modules. Generally, program modules include routines,programs, components, data structures, and other types of structuresthat perform particular tasks or implement particular abstract datatypes.

The aspects and functionalities described herein may operate via amultitude of computing systems including, without limitation, desktopcomputer systems, wired and wireless computing systems, mobile computingsystems (e.g., mobile telephones, netbooks, tablet or slate typecomputers, notebook computers, and laptop computers), hand-held devices,multiprocessor systems, microprocessor-based or programmable consumerelectronics, minicomputers, and mainframe computers.

In addition, according to an aspect, the aspects and functionalitiesdescribed herein operate over distributed systems (e.g., cloud-basedcomputing systems), where application functionality, memory, datastorage and retrieval and various processing functions are operatedremotely from each other over a distributed computing network, such asthe Internet or an intranet. According to an aspect, user interfaces andinformation of various types are displayed via on-board computing devicedisplays or via remote display units associated with one or morecomputing devices. For example, user interfaces and information ofvarious types are displayed and interacted with on a wall surface ontowhich user interfaces and information of various types are projected.Interaction with the multitude of computing systems with whichimplementations are practiced include, keystroke entry, touch screenentry, voice or other audio entry, gesture entry where an associatedcomputing device is equipped with detection (e.g., camera) functionalityfor capturing and interpreting user gestures for controlling thefunctionality of the computing device, and the like.

FIG. 4-6 and the associated descriptions provide a discussion of avariety of operating environments in which examples are practiced.However, the devices and systems illustrated and discussed with respectto FIGS. 4-6 are for purposes of example and illustration and are notlimiting of a vast number of computing device configurations that areutilized for practicing aspects, described herein.

FIG. 4 is a block diagram illustrating physical components (i.e.,hardware) of a computing device 400 with which examples of the presentdisclosure are be practiced. In a basic configuration, the computingdevice 400 includes at least one processing unit 402 and a system memory404. According to an aspect, depending on the configuration and type ofcomputing device, the system memory 404 comprises, but is not limitedto, volatile storage (e.g., random access memory), non-volatile storage(e.g., read-only memory), flash memory, or any combination of suchmemories. According to an aspect, the system memory 404 includes anoperating system 405/132 and one or more program modules 406 suitablefor running software applications 450/104. The operating system 405/132,for example, is suitable for controlling the operation of the computingdevice 400. According to an aspect, the operating system 405/132includes the FTL drive 114. Furthermore, aspects are practiced inconjunction with a graphics library, other operating systems, or anyother application program, and is not limited to any particularapplication or system. This basic configuration is illustrated in FIG. 4by those components within a dashed line 408. According to an aspect,the computing device 400 has additional features or functionality. Forexample, according to an aspect, the computing device 400 includesadditional data storage devices (removable and/or non-removable) suchas, for example, magnetic disks, optical disks, or tape. Such additionalstorage is illustrated in FIG. 4 by a removable storage device 409 and anon-removable storage device 410.

As stated above, according to an aspect, a number of program modules anddata files are stored in the system memory 404. While executing on theprocessing unit 402, the program modules 406 perform processesincluding, but not limited to, one or more of the stages of the method300 illustrated in FIG. 3. According to an aspect, other program modulesare used in accordance with examples and include applications such aselectronic mail and contacts applications, word processing applications,spreadsheet applications, database applications, slide presentationapplications, drawing or computer-aided application programs, etc.

According to an aspect, aspects are practiced in an electrical circuitcomprising discrete electronic elements, packaged or integratedelectronic chips containing logic gates, a circuit utilizing amicroprocessor, or on a single chip containing electronic elements ormicroprocessors. For example, aspects are practiced via asystem-on-a-chip (SOC) where each or many of the components illustratedin FIG. 4 are integrated onto a single integrated circuit. According toan aspect, such an SOC device includes one or more processing units,graphics units, communications units, system virtualization units andvarious application functionality all of which are integrated (or“burned”) onto the chip substrate as a single integrated circuit. Whenoperating via an SOC, the functionality, described herein, is operatedvia application-specific logic integrated with other components of thecomputing device 400 on the single integrated circuit (chip). Accordingto an aspect, aspects of the present disclosure are practiced usingother technologies capable of performing logical operations such as, forexample, AND, OR, and NOT, including but not limited to mechanical,optical, fluidic, and quantum technologies. In addition, aspects arepracticed within a general purpose computer or in any other circuits orsystems.

According to an aspect, the computing device 400 has one or more inputdevice(s) 412 such as a keyboard, a mouse, a pen, a sound input device,a touch input device, etc. The output device(s) 414 such as a display,speakers, a printer, etc. are also included according to an aspect. Theaforementioned devices are examples and others may be used. According toan aspect, the computing device 400 includes one or more communicationconnections 416 allowing communications with other computing devices418. Examples of suitable communication connections 416 include, but arenot limited to, radio frequency (RF) transmitter, receiver, and/ortransceiver circuitry; universal serial bus (USB), parallel, and/orserial ports.

The term computer readable media as used herein include computer storagemedia. Computer storage media include volatile and nonvolatile,removable and non-removable media implemented in any method ortechnology for storage of information, such as computer readableinstructions, data structures, or program modules. The system memory404, the removable storage device 409, and the non-removable storagedevice 410 are all computer storage media examples (i.e., memorystorage.) According to an aspect, computer storage media includes RAM,ROM, electrically erasable programmable read-only memory (EEPROM), flashmemory or other memory technology, CD-ROM, digital versatile disks (DVD)or other optical storage, magnetic cassettes, magnetic tape, magneticdisk storage or other magnetic storage devices, or any other article ofmanufacture which can be used to store information and which can beaccessed by the computing device 400. According to an aspect, any suchcomputer storage media is part of the computing device 400. Computerstorage media does not include a carrier wave or other propagated datasignal.

According to an aspect, communication media is embodied by computerreadable instructions, data structures, program modules, or other datain a modulated data signal, such as a carrier wave or other transportmechanism, and includes any information delivery media. According to anaspect, the term “modulated data signal” describes a signal that has oneor more characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, radiofrequency (RF), infrared, and other wireless media.

FIGS. 5A and 5B illustrate a mobile computing device 500, for example, amobile telephone, a smart phone, a tablet personal computer, a laptopcomputer, and the like, with which aspects may be practiced. Withreference to FIG. 5A, an example of a mobile computing device 500 forimplementing the aspects is illustrated. In a basic configuration, themobile computing device 500 is a handheld computer having both inputelements and output elements. The mobile computing device 500 typicallyincludes a display 505 and one or more input buttons 510 that allow theuser to enter information into the mobile computing device 500.According to an aspect, the display 505 of the mobile computing device500 functions as an input device (e.g., a touch screen display). Ifincluded, an optional side input element 515 allows further user input.According to an aspect, the side input element 515 is a rotary switch, abutton, or any other type of manual input element. In alternativeexamples, mobile computing device 500 incorporates more or less inputelements. For example, the display 505 may not be a touch screen in someexamples. In alternative examples, the mobile computing device 500 is aportable phone system, such as a cellular phone. According to an aspect,the mobile computing device 500 includes an optional keypad 535.According to an aspect, the optional keypad 535 is a physical keypad.According to another aspect, the optional keypad 535 is a “soft” keypadgenerated on the touch screen display. In various aspects, the outputelements include the display 505 for showing a graphical user interface(GUI), a visual indicator 520 (e.g., a light emitting diode), and/or anaudio transducer 525 (e.g., a speaker). In some examples, the mobilecomputing device 500 incorporates a vibration transducer for providingthe user with tactile feedback. In yet another example, the mobilecomputing device 500 incorporates input and/or output ports, such as anaudio input (e.g., a microphone jack), an audio output (e.g., aheadphone jack), and a video output (e.g., a HDMI port) for sendingsignals to or receiving signals from an external device. In yet anotherexample, the mobile computing device 500 incorporates peripheral deviceport 540, such as an audio input (e.g., a microphone jack), an audiooutput (e.g., a headphone jack), and a video output (e.g., a HDMI port)for sending signals to or receiving signals from an external device.

FIG. 5B is a block diagram illustrating the architecture of one exampleof a mobile computing device. That is, the mobile computing device 500incorporates a system (i.e., an architecture) 502 to implement someexamples. In one example, the system 502 is implemented as a “smartphone” capable of running one or more applications (e.g., browser,e-mail, calendaring, contact managers, messaging clients, games, andmedia clients/players). In some examples, the system 502 is integratedas a computing device, such as an integrated personal digital assistant(PDA) and wireless phone.

According to an aspect, one or more application programs 550/104 areloaded into the memory 562 and run on or in association with theoperating system 564/108. Examples of the application programs includephone dialer programs, e-mail programs, personal information management(PIM) programs, word processing programs, spreadsheet programs, Internetbrowser programs, messaging programs, and so forth. According to anaspect, the FTL drive 114 is loaded into memory 562. The system 502 alsoincludes a non-volatile storage area 568 within the memory 562. Thenon-volatile storage area 568 is used to store persistent informationthat should not be lost if the system 502 is powered down. Theapplication programs 550/104 may use and store information in thenon-volatile storage area 568, such as e-mail or other messages used byan e-mail application, and the like. A synchronization application (notshown) also resides on the system 502 and is programmed to interact witha corresponding synchronization application resident on a host computerto keep the information stored in the non-volatile storage area 568synchronized with corresponding information stored at the host computer.As should be appreciated, other applications may be loaded into thememory 562 and run on the mobile computing device 500.

According to an aspect, the system 502 has a power supply 570, which isimplemented as one or more batteries. According to an aspect, the powersupply 570 further includes an external power source, such as an ACadapter or a powered docking cradle that supplements or recharges thebatteries.

According to an aspect, the system 502 includes a radio 572 thatperforms the function of transmitting and receiving radio frequencycommunications. The radio 572 facilitates wireless connectivity betweenthe system 502 and the “outside world,” via a communications carrier orservice provider. Transmissions to and from the radio 572 are conductedunder control of the operating system 564/108. In other words,communications received by the radio 572 may be disseminated to theapplication programs 550/104 via the operating system 564/108, and viceversa.

According to an aspect, the visual indicator 520 is used to providevisual notifications and/or an audio interface 574 is used for producingaudible notifications via the audio transducer 525. In the illustratedexample, the visual indicator 520 is a light emitting diode (LED) andthe audio transducer 525 is a speaker. These devices may be directlycoupled to the power supply 570 so that when activated, they remain onfor a duration dictated by the notification mechanism even though theprocessor 560 and other components might shut down for conservingbattery power. The LED may be programmed to remain on indefinitely untilthe user takes action to indicate the powered-on status of the device.The audio interface 574 is used to provide audible signals to andreceive audible signals from the user. For example, in addition to beingcoupled to the audio transducer 525, the audio interface 574 may also becoupled to a microphone to receive audible input, such as to facilitatea telephone conversation. According to an aspect, the system 502 furtherincludes a video interface 576 that enables an operation of an on-boardcamera 530 to record still images, video stream, and the like.

According to an aspect, a mobile computing device 500 implementing thesystem 502 has additional features or functionality. For example, themobile computing device 500 includes additional data storage devices(removable and/or non-removable) such as, magnetic disks, optical disks,or tape. Such additional storage is illustrated in FIG. 5B by thenon-volatile storage area 568.

According to an aspect, data/information generated or captured by themobile computing device 500 and stored via the system 502 is storedlocally on the mobile computing device 500, as described above.According to another aspect, the data is stored on any number of storagemedia that is accessible by the device via the radio 572 or via a wiredconnection between the mobile computing device 500 and a separatecomputing device associated with the mobile computing device 500, forexample, a server computer in a distributed computing network, such asthe Internet. As should be appreciated such data/information isaccessible via the mobile computing device 500 via the radio 572 or viaa distributed computing network. Similarly, according to an aspect, suchdata/information is readily transferred between computing devices forstorage and use according to well-known data/information transfer andstorage means, including electronic mail and collaborativedata/information sharing systems.

Implementations, for example, are described above with reference toblock diagrams and/or operational illustrations of methods, systems, andcomputer program products according to aspects. The functions/acts notedin the blocks may occur out of the order as shown in any flowchart. Forexample, two blocks shown in succession may in fact be executedsubstantially concurrently or the blocks may sometimes be executed inthe reverse order, depending upon the functionality/acts involved.

The description and illustration of one or more examples provided inthis application are not intended to limit or restrict the scope asclaimed in any way. The aspects, examples, and details provided in thisapplication are considered sufficient to convey possession and enableothers to make and use the best mode. Implementations should not beconstrued as being limited to any aspect, example, or detail provided inthis application. Regardless of whether shown and described incombination or separately, the various features (both structural andmethodological) are intended to be selectively included or omitted toproduce an example with a particular set of features. Having beenprovided with the description and illustration of the presentapplication, one skilled in the art may envision variations,modifications, and alternate examples falling within the spirit of thebroader aspects of the general inventive concept embodied in thisapplication that do not depart from the broader scope.

I claim:
 1. A computer-implemented method for writing data to storage,comprising: receiving a write request at an I/O manager to write data toa storage device; establishing a divergence point by the I/O managerfrom a first thread to a second thread based on the write request; onthe first thread, processing the write request and storing one or morewrites of data in a queue; on the second thread, a flushless transactionlayer manager executing the one or more writes of data to the storagedevice, wherein the second thread executes the one or more writes ofdata to the storage device asynchronously while the first threadcontinues to process the write request and store writes of data in thequeue; and receiving by the I/O manager an indication of a completion ofexecuting the one or more writes of data to the storage device, whereinthe indication of the completion establishes a convergence of the firstthread and the second thread.
 2. The computer-implemented method ofclaim 1, wherein processing the write request comprises analyzing thedata for identifying one or more pieces of changed information.
 3. Thecomputer-implemented method of claim 2, wherein storing one or morewrites of data in a queue comprises: copying the one or more pieces ofchanged information in one or more buffers; and placing the one or morebuffers in the queue.
 4. The computer-implemented method of claim 3,wherein executing the one or more writes of data to the storage devicecomprises: determining whether the queue is empty; and when the queue isnot empty, issuing a command to a storage device controller to write thechanged information in the buffer to a storage medium.
 5. Thecomputer-implemented method of claim 1, wherein after convergence of thefirst thread and the second thread, reading the stored data into acache.
 6. A system for writing data to storage, comprising: one or moreprocessors for executing programmed instructions; memory, coupled to theone or more processors, for storing program instruction steps forexecution by the one or more processors; an I/O manager operable to:receive a write request to write data to a storage device; establish adivergence point from a first thread to a second thread; process thewrite request; and store one or more writes of data in a queue; and aflushless transactional layer drive operable to execute the one or morewrites of data to the storage device on the second thread and furtheroperable to execute the one or more writes of data to the storage deviceasynchronously while the I/O manager continues to process the writerequest and store writes of data in the queue.
 7. The system of claim 6,wherein the I/O manager is further operable to receive an indication ofa completion of executing the one or more writes of data to the storagedevice.
 8. The system of claim 7, wherein the indication of thecompletion establishes a convergence of the first thread and the secondthread.
 9. The system of claim 6, wherein in processing the writerequest, the I/O manager is operable to call an analysis engine toanalyze the data for identifying one or more pieces of changedinformation.
 10. The system of claim 9, wherein in storing one or morewrites of data in a queue, the I/O manager is operable to: copy the oneor more pieces of changed information in one or more buffers; and placethe one or more buffers in a queue.
 11. The system of claim 10, whereinin executing the one or more writes of data to the storage device, theflushless transactional layer drive is operable to: determine whetherthe queue is empty; and when the queue is not empty, issue a command toa storage device controller to write the changed information in thebuffer to a storage medium.
 12. The system of claim 6, wherein afterconvergence of the first thread and the second thread, the I/O manageris further operable to read the stored data into a cache.
 13. One ormore computer storage media storing computer-usable instructions that,when used by one or more computing devices, cause the one or morecomputing devices to perform a method for writing data to storage, themethod comprising: receiving a write request to write data to a storagedevice; establishing a divergence point from a first thread to a secondthread based on the write request; on the first thread, the one or morecomputing devices: analyzing the data for identifying changedinformation from a last-saved version; copying the changed informationinto one or more empty buffers; and enqueuing the one or more buffers ina queue; and on the second thread, the one or more computing devices:executing writes of the changed information from the one or more buffersto the storage device, wherein the second thread executes writes of thechanged information from the one or more buffers to the storage deviceasynchronously while the first thread continues to process the writerequest and enqueue changed information.
 14. The one or more computerstorage media of claim 13, further comprising executing writes of thechanged information from the one or more buffers to the storage device,wherein the indication of the completion establishes a convergence ofthe first thread and the second thread.
 15. The one or more computerstorage media of claim 14, wherein after convergence of the first threadand the second thread, reading the stored data into a cache.
 16. The oneor more computer storage media of claim 13, wherein executing writes ofthe changed information from the one or more buffers to the storagedevice comprises: determining whether the queue is empty; and when thequeue is not empty, issuing a command to a storage device controller towrite the changed information in the buffer to a storage medium.
 17. Theone or more computer storage media of claim 13, wherein executing writesof the changed information from the one or more buffers to the storagedevice comprises writing the changed information to a disk drive tostore on a disk.